Embodiments of the present invention relate to a circuit and method for a light emitting diode (LED) lighting system with predictive forward voltage for a pulse width modulated (PWM) current loop.
Light emitting diode (LED) lighting systems are presently used for many applications such as automobiles, homes, businesses, and security systems. LED lighting systems provide illumination more efficiently than incandescent lighting systems, since they expend much less power in heat generation and are much more reliable. LED lighting systems are also much more flexible than fluorescent lighting systems, since they are more tolerant to environmental conditions such as shock, contamination, and temperature. Moreover, they may be operated with controlled duty cycles to adjust brightness. LED lighting systems are often configured as series-connected LEDs due to their relatively small forward voltage. As such, the series connection or string of LEDs may produce substantial electromagnetic interference (EMI) due to abrupt changes in the relatively large forward current and high series inductance. The EMI may adversely affect nearby electronic communication systems. Filter circuits and shielding may reduce EMI but compromise system efficiency and increase cost.
The present inventors, therefore, recognize that still further improvements are possible. Accordingly, the preferred embodiments described below are directed toward improving upon LED lighting systems of the prior art.